Wear weighting function generator for the determination of the proper aiming of a gun



R. G. cLuTTERBucK ET AL 3,538,3 WEAR WEIGHTING FUNCTION GENERATOR FORTHE DETERMINATION OF THE PROPERV AIMING OF A GUN 2 Sheets-Sheet 1 FiledAug. 2l, 1968 VIIJ.

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WEAR WEIGHTING FUN OF THE PROPER AIMING OF A GUN 2 Sheets-Sheet 2 FiledAug. 21, 196s U.S. Cl. 23S-193 8 Claims ABSTRACT F THE DISCLOSURE Indetermination of the proper aiming of a gun, the effects of wear in thegun tube caused by previous rounds must be considered. A firing sensorconnected to the gun ring mechanism signals gun firing. An ammunitionselector multiplies this gun tiring signal by any selected one of aplurality of gun tube wear factors, depending upon the type ofammunition fired, to result in a gun tube wear factor for thatparticular round. These factors are totalized so that a counter carriesthe total wear factor accumulated since the gun tube was new. Thecounted total is stored in a non-volatile memory. The memory ispreferably a ferrite core memory or the like, and the counter is amultibit solid-state counter. The counter output signal is connected toa digital-toanalog converter, the signal of which corresponds to guntube wear since the gun tube was new, and is employed as a correctionfactor in the gun fire control computer.

BACKGROUND This invention is directed to a Wear weighting functiongenerator which has an output signal which corresponds to the amount ofwear in a gun tube, which signal can be employed as a correction factorin a gun tire control computer.

The velocity of a projectile as it leaves the muzzle of a gun is afunction not only of the individual characteristics of the projectileand its driving charge, but it is also a function of the condition ofthe gun barrel. The change in muzzle velocity due to wear has beenpreviously recognized, and previous gun computers have employed inputscorresponding to Wear for the correction of gun direction. In theprevious units, the gunner was required to periodically measure the gunbore, preferably both at the chamber end and at the muzzle end. After hecompared these measurements with prescribed standards, he manually madean adjustment on the gun computer in accordance with his findings as tothe state of wear. Of course, during battle, wear would proceed withoutgiving the gunner the opportunity for these required periodicmeasurements. As a result, at the time when correct aiming was mostneeded, the change in muzzle Velocity due to wear was not continuouslyupdated and inserted into the gun computer, with adverse aiming effects.Other more sophisticated methods have also been attempted.

As an additional factor, gun computers are subject to shocks of highorders of acceleration. The gun shock itself, of course, it notpermitted to put out of action the gun computer. Furthermore, a directartillery hit upon the gunsupporting structure, which does not directlystrike the gun computer should not put the gun computer out of service.Thus, those items directly damaged can be replaced and the gun will beback in service. Furthermore, if the hit is not of a critical nature,the gun can remain in service. Such resistance to high accelerations isbest accomplished by the use of solid-state circuitry.

nite States aten SUMMARY In order to aid in the understanding of thisinvention, it can be stated in essentially summary form that it isdirected to a wear weighting function generator which totalizes the wearin a gun tube resulting from the firing of a plurality of roundstherethrough, even when the rounds are of diiferent wear-poducingnature, for employing the wear function as a correction in a gun tirecontrol computation. The wear weighting function is generated by inputsignals representing both the number of rounds, and the wear-producingcharacter of each individual round. These individual round wear factorsare totalized in a counter, and a parallel non-volatile memory storesthe weighted wear function so that a value corresponding to wear isremembered through power cessation. The output of a counter serves as aneffective full charge signal for employment in calculation of change ofmuzzle velocity due to wear, as a correction factor to the gun recontrol cornputer.

Accordingly, it is an object of this invention to provide a wearWeighting function generator which employs several inputs, and totalizesthem to hold a total count corresponding to the amount of wear in a guntube. It is a further object to provide a non-volatile storage for thecounted total Wear function so that upon power failure, or normal systemturn off, the number corresponding to total wear is retained. It is afurther object to provide a solid state wear Weighting functiongenerator which is resistant to high accelerations, and still retainsits count. It is still another object to provide a counter whichtotalizes a number corresponding to total wear, together with a parallelmemory therefor so that the memory can serve to reset the counter asrequired. It is another object to provide a ferrite memory as the memoryunit. Other objects and advantages of this invention will becomeapparent from a study of the following portion of the specification, theclaims and the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. l is a block diagram showing theWear weighting function generator.

FIG. 2 is a more detailed schematic drawing showing the details of theeffective full charge multiplier as it is related to the rest of thegenerator.

DESCRIPTION The wear Weighting function generator of this invention isgenerally indicated at 402 in FIG. 1. It is associated with gun 404which has a bore which wears out upon firing thereof. Presuming that thegun 404 is capable of tiring a plurality of different types ofarnmunition, and these different types cause different amounts of Wearfor each shot, it is necessary to provide signals relating to the typeof ammunition, and relating to the number of firings.

Firing switch 406 is mechanically connected to gun 404 so that itmomentarily closes upon each gun firing. Preferably, it is actuated bythe recoil mechanism of the gun. Thus, a firing signal is transmitted tothe effective full charge rate multiplier 40S upon the firing of eachround. Another signal delivered to the EFC multiplier is from ammunitionselector switch 410.

Assuming four different types of ammunition to be fired through gun 404,exemplary values of wear rates and wear multipliers are given in thetable below:

The number of rounds to wearout, for particular ammunition, is foundexperimentally. Any convenient means to determine wearout of the barrelcan be used, including micrometer measurement of the gun bore, or bychange in muzzle velocity, as compared to a new barrel. The least commonmultiple of the number of rounds to wearout is 3,000. The wearmultiplier in the table is the least common multiple divided by thenumber of rounds of a particular ammunition to wearout. Thus, the wearmultiplier is a relative value of wear in the gun barrel, which relatesthe amount of wear caused in the barrel by the different ammunitions.

With input signals from the firing switch 406 and ammunition selectorswitch 4.10, the effective full charge rate multiplier multiplies theround red by its wear multiplier. This amount of effective full chargeby that particular round is delivered to counter 412 which totalizes theeffective full charge units received from the EFC rate multiplier. Thisamount of effective full charge by that particular round is also appliedto the read-write control 424 in order to initiate the write operation,thereby allowing the counter 412 to update the memory 420. Output ofcounter 412 is delivered to digital-to-analog converter 414, which issimilar to the digital to analog converter described in U.S. Pat.2,993,202 issued July 18, 1961, by signal line 416 so that the output ofwear weighting function generator 402 appears in signal line 418 as ananalog value. It is suitably employed in a gun fire control computer tocompensate aiming in accordance with the total wear of the barrel.

In view of the fact that guns to which such aiming equipment is appliedare subject to power failure and are subject to being placed in storagewith power shutdown for considerable periods, when counter 412 is ofsolid state, it normally loses count upon power shutdown. Thus, memory420, which may be similar to the memory described in U.S. Pat. 2,933,720issued Apr. 19, 1960, is associated with counter 412 in order to providethe correct count to the counter after such a power shutdown. Powercondition detector 422 is connected to the electric power source whichserves to retain the count in the counter. Power condition detector 422is connected to read-write control 424, which is in turn connected tomemory 420 for the purpose of providing in the memory a count of thetotal on counter 412 when power is olf, and for the purpose of writinginto the counter the count when power is restored. The power conditiondetector 422 may be similar to the circuitry shown in FIG. 3 of U.S.Pat. 3,321,747 issued May 23, 1967. Furthermore, the read-write control424 may be similar to that described and shown from page 19-13 to page19-21 in volume 2 of the Handbook of Automation Computation and Controlpublished by John Wiley & Sons, Inc., New York (1959). Counter 412 caneither update memory 4201 with each count of memory 420 can be connectedto interrogate counter 412 upon incipient power failure and store thememory in the counter. Memory 420 is preferably a ferrite core memory,although any convenient memory system can be employed.

`Referring to FIG. 2, a schematic diagram in more detail of theeffective full charge multiplier is shown therein, in connection withassociated equipment. Clock 426 either generates a square wave ofappropriate frequency, or squares off an available frequency. In someequipment with which the wear weighting function generator is employed,400 cycle alternating current is available. In such cases, clock 426need only square the available freqency. The output from firing switch406 and clock 426 are inputs to AND gate 428. The output of AND gate 428goes to OR gate 430. The output of OR gate 430 is connected to counter432.

In the example illustrated, counter 432 is a four-bit counter capable ofcounting to 16. The four outputs from the four bits of counter 432 areconnected to OR gate 434. The output of OR gate 434 is connected to ANDgate 436 which also receives the clock signal as an input thereto. Theoutput of AND gate 436 is the other input to OR gate 430. Counter 432has at least one high state output whenever the count thereon is otherthan zero. Thus, as long as the count is other than zero, there is asignal to OR gate 434, which provides energization to AND gate 436 sothat the clock pulse passes through OR gate 430 to keep the counter 432counting. This continues until the full count of 16 is made by thecounter, when all of the counter outputs are at zero so that there is nooutput from OR gate 434 into AND gate 436. Thereupon, the counter stopsuntil the next firing switch energization. This system provides 16pulses in line 438 each time tiring switch 416 is actuated.

Line 438 is connected to the input of binary sealer 440 which hassections 442, 444, 446, and 448, which may be bistable multivibrators orflip-flops. Thus, each time counter 432 goes through its 16 counts, itdelivers 8 counts to AND gate 452, 4 counts to AND gate 454, 2 counts toAND gate 456, and 1 count to AND gate 458. The ammunition selectorswitch 410 is connected to each one of AND gates 452 through 458 so thatthe number of counts desired can be selected by selecting particularones of the AND gates.

The following table indicates the switch pattern of the ammunitionselector switch to obtain the desired number of counts. To accomplishthis switch pattern, the ammunition selector switch 410 may comprisefour manually operable two-position switches (not shown), each having a"0 output when open and a l output when closed. The switch patternindicates the high or low state of the lines from the ammunitionselector switch to AND gates 452 through 458, reading from top to bottomin FIG. 2.

The outputs of AND gates 452 through 458 are connected to OR gate 460 sothat the output is totalized and the signal into line 416 is theeffective full charge count for the round just fired, and as previouslystated, this is delivered to counter 412 through signal line 462 to addto the count on counter 412 the factor corresponding to wear for thefiring of the latest round. As a round having a different wear factor isloaded, the ammunition selector switch 410 is changed to a positioncorresponding to the new round, so that upon ring thereof the wearfactor for that round is totalized in counter 412.

This invention having been described in its preferred embodiment, it isclear that it is susceptible toi numerous modications and embodimentswithin the ability of those skilled in the art and without the exerciseof the inventive faculty. Accordingly, the scope of this invention isdefined by the scope of the following claims.

What is claimed is:

1. A wear weighting function generator for totalizing and emitting asignal corresponding to wear caused on a unit by separate acts whicheach cause a different but predetermined amount of wear on the unit,said wear weighting function generator comprising:

a detector for detecting an act on the unit;

a selector for selecting a value related to the amount of Wear caused bythe act on the unit;

a multiplier, said detector and said selector being connected to saidmultiplier so that the multiplier multiplies the number of acts timesthe value related to the amount of wear;

a counter, said multiplier being connected to said counter so that saidcounter totalizes the products received from said multiplier;

a memory connected to said counter, said memory 5 storing the count ofsaid counter so that upon loss of count by said counter said memory canreset said counter, said counter emitting a signal corresponding to thenumber of acts causing wear on said unit each times its wear factor sothat the emitted signal is related to total wear on said unit.

2. The Wear weighting function generator of claim 1 wherein said counteris a solid-state counter which is subject to loss of count upon powerfailure, and said memory is a non-volatile memory so that said memoryholds the count during periods of power cessation and can reset saidcounter.

3. The wear weighting function generator of claim 2 wherein a powercondition detector is connected to the source of power which powers saidcounter, said power condition detector .being connected to a read-writecontrol, said read-write control being connected to said memory so thatupon power cessation, said memory retains the count of said counter, andupon restoration of power, said power condition detector causes saidmemory to reset said counter to the remembered value.

4. The wear Weighting function generator of claim 3 wherein said unit isa gun capable of tiring different ammunitions which cause diierentamounts of wear, said detector is a firing switch which is connected tosaid gun and detects each tiring of said gun, and said selector is anammunition selector switch which is settable to different values inaccordance with the relative wear of the different types of ammunitionrable by said gun, so that the signal emitted by said counter is relatedto the total amount of wear in said gun.

5. The wear Weighting function generator of claim 1 wherein saidmultiplier comprises a counter, said act detector and a clock having aninput to said counter, the output of said counter being connected to theinput of said counter so that said counter counts to one more than itsfull count and thereupon stops so that the input to said counterreceives as many pulses as the full count of said counter, a binaryScaler connected to the input of said counter, said binary scaler havinga plurality of outputs, each emitting a number of counts, said outputsof said scaler being connected to scaler output AND gates, said selectorbeing connected to said Scaler output AND gates to energize particularones of said scaler output AND gates, the outputs of said Scaler outputAND gates being summed together in a summer so that said selectorselects the number of counts out of said summer.

6. The wear weighting function generator of claim 5 wherein there areiirst and second AND gates, said clock being connected to said rst andsecond AND gates, said detector being connected to said rst AND gate andthe output of said counter being connected to the input of said secondAND gate, the outputs of said rst and second AND gates being connectedtogether to a counter input OR gate, 4with the output of said counterinput OR gate being connected to the input of said counter, the outputof said counter input OR gate being also connected to the input of saidbinary scaler.

7. The wear weighting function generator of claim 6 wherein said unit isa gun, and said detector is a ring switch which emits a signal each timesaid gun is iired so that upon gun tiring said counter is energizedthrough said rst AND gate.

8. The wear weighting function generator of claim 7 wherein saidselector is an ammunition selector switch connected to said scaleroutput AND gates so as to energize appropriate of said Scaler output ANDgates in accordance with the relative wear of a particular type ofselected ammunition tired in said gun.

References Cited UNITED STATES PATENTS 3,102,451 9/1963 Campbell 89-413,136,992 6/1964 French 89-41 X 3,260,107 7/1966 Rosen 73-167 3,313,2094/1967 Thompson 89-41 3,339,457 9/1967 Pun 235-6l.5 X 3,405,599 10/ 1968`Barlow et al.

3,443,476 5/ 1969 Heider et al.

MALCOLM A. MORRISON, Primary Examiner I. F. RUGGIERO, Assistant ExaminerU.S. Cl. X.R.

